Sieve of Eratosthenes for finding Prime numbers and Twin Prime numbers

twinPrimeNumbers.php

<?php

/**
 * Run this code with: "php -n <file.php>" to make sure no configuration will be used
 * so xdebug will not be used either.
 */

declare(strict_types=1);

include __DIR__ . '/vendor/autoload.php';

use loophp\collection\Collection;

function primesGenerator(Iterator $iterator): Generator
{
    yield $primeNumber = $iterator->current();

    $iterator = new \CallbackFilterIterator(
        $iterator,
        fn(int $a): bool => $a % $primeNumber !== 0
    );

    $iterator->next();

    return $iterator->valid() ?
        yield from primesGenerator($iterator):
        null;
}

function integerGenerator(int $init = 1, callable $succ): Generator
{
    yield $init;

    return yield from integerGenerator($succ($init), $succ);
}

$primes = primesGenerator(integerGenerator(2, fn(int $n): int => $n + 1));

$limit = 1000000;

// Create a lazy collection of Prime numbers from 2 to infinity.
$lazyPrimeNumbersCollection = Collection::fromIterable(
    primesGenerator(
        integerGenerator(2, static fn ($n) => $n + 1)
    )
);

// Print out the first 1 million of prime numbers.
foreach ($lazyPrimeNumbersCollection->limit($limit) as $prime) {
    var_dump($prime);
}

// Create a lazy collection of Prime numbers from 2 to infinity.
$lazyPrimeNumbersCollection = Collection::fromIterable(
    primesGenerator(
        integerGenerator(2, static fn ($n) => $n + 1)
    )
);

// Find out the Twin Prime numbers by filtering out unwanted values.
$lazyTwinPrimeNumbersCollection = Collection::fromIterable($lazyPrimeNumbersCollection)
    ->zip($lazyPrimeNumbersCollection->tail())
    ->filter(static fn (array $chunk): bool => 2 === $chunk[1] - $chunk[0]);

foreach ($lazyTwinPrimeNumbersCollection->limit($limit) as $prime) {
    var_dump($prime);
}